An aortic dissection is a dangerous condition with high mortality rates. In an aortic dissection, a tear typically develops in the intima of the aorta that propagates along the vessel wall delaminating the inner layer of the aorta from the outer layer. Blood enters the space between the layers creating a false lumen. Several additional tears or entry points can be created between the true lumen of the aorta and the false lumen. In the acute phase, dissections may close a perfusion from the aorta to vital organs. In the chronic phase, the weakened tissue can develop into an aneurysm and ultimately rupture. Dissections involving the ascending aorta are referred to as Type A dissections. Dissections only involving the descending aorta are referred to as Type B dissections.
Current treatments for dissections include medical management to lower the blood pressure of the patient and reduce the hemodynamic stresses on the diseased vessel. If dissections are symptomatic, surgical intervention is necessary. Portions of the diseased aorta are replaced by a surgical graft and the dissection flap is reattached. More recently, stent grafts have been used to close the primary entry point into the false lumen with the goal to thrombose the false lumen and maintain patency of the true lumen.
Endovascular treatment of aortic dissections with a thoracic aortic stent graft may risk inter-operative and post-operative complications. The catheter delivery systems of thoracic stent grafts typically have a profile of 20-24 Fr, requiring a cut-down or conduit for delivery. Vessel damage by the large delivery catheters is common. Stent grafts are difficult to deploy accurately in the thoracic aorta due to the high blood flow through the thoracic aorta. The proximal end of the stent graft, particularly uncovered stent sections, may cause the dissection tear to propagate proximally into the aortic arch.
There is a clear need for an improved method to treat aortic dissections. The current application describes certain embodiments, which provide a solution to the treatment of aortic dissections while minimizing the impact on the aorta.